Iron Horse Park, Massachusetts

This 553-acre train yard used to be the Boston and Maine Railroad's largest maintenance yard, back when B&M was the biggest railroad company in the state. Steam locomotives, diesels, and passenger cars were all maintained at this site over the years. It is still home to several industries, including Guilford Rail System (now known as Pam Am Railways, Inc.), which bought the remains of B&M. Decades of industrial use have left quite a bit of toxic waste, resulting in the site being placed on the EPA's National Priority List in 1984, due to concerns over lagoons of toxic sludge, as well as soil, surface water, groundwater, and sediment contamination. The woods behind the yard have several asbestos dumps, as B&M permitted other companies to use its property for asbestos disposal.